| Subject | English | Bulgarian |
| agric. | open model | открит модел |
| comp., MS | Open Systems Interconnection model | Отворен модел за връзка между мрежови системи (A networking model introduced by the International Organization for Standardization (ISO) to promote multi-vendor interoperability. OSI is a seven-layered conceptual model consisting of the application, presentation, session, transport, network, data-link, and physical layers) |
| commun., comp. | open systems interconnection reference model | еталонен седемслоен модел OSI |
| commun., comp. | open systems interconnection reference model | еталонен модел за открити мрежи |
| gen. | open systems interconnection reference model | еталонен модел OSI-ISO |